A wide range of digital display systems incorporate liquid-crystal display (LCD) technology. LCD displays are found in smartphones, tablet and laptop computers, and in video monitors for televisions and desktop computers. A typical LCD display includes an image-forming, liquid-crystal layer positioned in front of a backlight.
Ideally the LCD backlight should emit enough light to make the display viewable in bright ambient conditions. A highly emissive backlight, however, may consume excessive power. In smartphones and tablet computers, for instance, the power to operate the LCD backlight may be a significant fraction of the overall power budget. As a result, tablets and smartphones must be designed with relatively thick, relatively heavy batteries, or be subject to frequent recharge, which shortens lifetime. In a stationary display, excessive power consumption by the LCD backlight increases operating costs, makes the system less environmentally compliant, and may cause unwanted heating